If I remember correctly, they also had Vorta doctors trying to sure the section 31 disease. So either the Vorta must also be bred to have (some) research skills -or perhaps a certain subset of all Vorta-, which would probably require independent thinking to a certain degree, but in a different way than a political administrator would need, or the Dominion tried just to make do with what they got.
Well Doctors could in theory be used to create diseases as well as cure them i.e. The Quickening virus